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Bug #13648
closed
[PATCH] Nested map of Enumerator::Lazy with packed values gives wrong result
Status:
Closed
Assignee:
-
Target version:
-
ruby -v:
ruby 2.5.0dev (2017-06-09 trunk 59052) [x86_64-linux]
Description
This test case ends up with the following result.
class Step
include Enumerable
attr_reader :current, :args
def initialize(enum)
@enum = enum
@current = nil
@args = nil
end
def each(*args)
@args = args
@enum.each do |v|
@current = v
if v.is_a? Enumerable
yield *v
else
yield v
end
end
end
end
a = Step.new([[1, 2]])
assert_equal([[[1, 2]]], a.lazy.map {|*args| args}.map {|*args| args}.to_a)
<[[[1, 2]]]> expected but was
<[[1, 2]]>.
Here, [[[1, 2]]] is expected because:
- An array should be created with the first map, which results in
[1, 2]. - The array should be wrapped in another array with the second map, which results in
[[1, 2]]. - The array should be wrapped in another array with to_a, which results in
[[[1, 2]]].
However, it returns [[1, 2]] because:
- An array will be created with the first map, which results in
[1, 2]. - However, the array will be internally considered as "packed" and the unpacked arguments will be passed to the second map.
- The second map wraps them into another array, which results in
[1, 2]. - The array will be wrapped in another array with to_a, which results in
[[1, 2]].
I have attached the test case and a fix. The fix marks values returned by blocks are not packed.
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